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The analysis of trace gas emissions from landfills

  • Authors: Rubidge, Gletwyn Robert
  • Date: 2000
  • Subjects: Gases, Asphyxiating and poisonnous , Gases -- Analysis , Sanitation -- Environmental engineering
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10983 , http://hdl.handle.net/10948/d1006341 , Gases, Asphyxiating and poisonnous , Gases -- Analysis , Sanitation -- Environmental engineering
  • Description: Numerous informal houses have been built on and adjacent to a landfill in iBayi, Port Elizabeth, South Africa, which accepted domestic and industrial waste. Formal housing surrounds most of the site at a greater distance - some 60 m, or further, from the landfill. Both formal and informally housed residents complain of odours, burning eyes, sore throats and headaches - symptoms which they believed were caused by the landfill. The landfill gas and ambient air were analyzed to classify and quantify the VOCs (volatile organic compounds) emitted and then to compare the quantitative data with recognised standards to establish if the residents are at risk. Eighteen target (potentially hazardous) VOCs were quantified. A wide variety of compounds were detected in both the ambient air and landfill gas. The results of the VOC analyses were similar to those of other workers in both the qualitative and quantitative studies. The concentrations of the VOCs were mostly lower than the TLV (threshold limit values) values, but exceeded the MRLs (minimum recommended levels). The combined concentrations of the VOC’s in the ambient air either approached or exceeded the limit values for combined exposure thus indicating that a potential health hazard exists. One third of the VOCs were detected in both the ambient air and the subsurface gas, however, external pollution sources also appear to contribute to the VOC concentrations ambient air. Dangerously high methane concentrations were repeatedly detected in the landfill gas amongst the informal houses. There was a vast improvement in the aesthetic qualities of the landfill since the disposal restriction to accept only domestic refuse and building rubble in July 1997. The ambient air was less odorous and landfill site littered. Fewer informal recyclers were present and their concomitant squabbling over valuables had almost vanished. The management of the iBayi landfill holds much room for improvement. There is potential for serious injury or even death if no action is taken to remedy the problems at the iBayi landfill. A holistic solution will have to be found to make the landfill a safe neighbour. Some complementary analyses (such as pH, heavy metal concentrations in the water and sediments etc.) were performed on the leachate and water surrounding the landfill.
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  • Date Issued: 2000

The biology of commercially important fish species and a preliminary assessment of the fisheries potential of Katse Dam, Lesotho

  • Authors: Nthimo, Mokitinyane Francis
  • Date: 2000
  • Subjects: Fishes -- Lesotho -- Katse dam , Fishes -- Physiology , Rainbow trout , Barbus aeneus , Labeo , Katse dam (Lesotho) , Fisheries -- Lesotho -- Katse dam , Fishery management -- Lesotho
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5238 , http://hdl.handle.net/10962/d1005081 , Fishes -- Lesotho -- Katse dam , Fishes -- Physiology , Rainbow trout , Barbus aeneus , Labeo , Katse dam (Lesotho) , Fisheries -- Lesotho -- Katse dam , Fishery management -- Lesotho
  • Description: The construction of the Katse dam was completed in 1996. The dam started filling in 1995 and reached full capacity in early 1998. It forms part of Phase 1A of the Lesotho Highlands Water Project (LHWP). The main aim of the project is to provide revenue to Lesotho, by transferring water from the catchment of the Senqu (Orange) River in Lesotho to South Africa’s major industrial and population centres. During the implementation of the project, an estimated 130 people were displaced. However, the most serious impact has been the loss of the traditional way of life in the form of arable and grazing land as a consequence of inundation. One of the obligations of the project is to ensure that the standard of living of those affected by the project is not impaired. The Lesotho Highlands Development Authority identified a number of rural development projects, which included fisheries development. This study is an integral part of fisheries development in Lesotho. The aim of this study was to gain an understanding of the biology and the demographics of the fish species in the lake. This information would serve as the basis for the development of a management plan for the sustainable utilisation of the fisheries resources. To achieve this aim, the following specific objectives were addressed: 1. Investigation of the biology of the three principal species. 2. Description of the key population parameters (growth, mortality & recruitment). 3. Investigation of the distribution and relative abundance of the three species. The three principal species in the Katse dam are rainbow trout, Oncorhynchus mykiss, and the two cyprinids, Barbus aeneus and Labeo capensis. Sectioned otoliths were used to age O. mykiss while both otoliths and scales were used to age B. aeneus and L. capensis. Marginal zone analysis revealed that slow growth was experienced in winter for the three species. The maximum-recorded age for both B. aeneus and L. capensis was 12 years while O. mykiss reached 4 years. There was no significant difference in growth rates of the different sexes and growth was best described by the 3 parameter Von-Bertalanfy growth model as Lt = 603[1-e⁻°·¹⁵⁽t ⁺ °·°³⁾] for B. aeneus, Lt = 526[1-e⁻°·²¹⁽t ⁺ °·⁹⁾] for O. mykiss and Lt = 521[1-e⁻°·¹⁷⁽t ⁺ °·²¹⁾] for L.capensis. Male and female O. mykiss attained 50% sexual maturity (Lm₅₀) at 235 and 275mm FL, respectively. There was no difference in Lm₅₀ for male and female B. aeneus and L. capensis. B. aeneus reached sexual maturity at 285mm FL while L. capensis reached sexual maturity at 244mm. Both cyprinid species spawned in summer (November to January) while O. mykiss spawned in winter (May to August). The mean total mortality rate (Z) estimated from catch curves and Butterworth et al (1989) equation was 0.72 yr⁻¹ for B. aeneus, 0.62 yr⁻¹ for L. capensis and 1.32 yr⁻¹ for O. mykiss. The estimate of natural mortality was 0.41 yr⁻¹ for both B. aeneus and L. capensis and 0.81yr⁻¹ for O. mykiss.
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  • Date Issued: 2000

The comparative value of wild and domestic plants in home gardens of a South African rural village

  • Authors: High, Christopher , Shackleton, Charlie M
  • Date: 2000
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/181907 , vital:43779 , xlink:href="https://doi.org/10.1023/A:1006247614579"
  • Description: Rural inhabitants make considerable use of wild resources from communal areas around their settlements, as well as from arable and residential plots. These wild resources compete with the main crops planted in arable plots and home gardens, but play a significant economic and nutritional role in rural livelihoods. This paper reports upon a conservative financial evaluation of the wild plant resources harvested from home gardens and arable plots by inhabitants of rural village in the Bushbuckridge lowveld (South Africa), and examines their importance relative to other domesticated crops. On average, each household made use of four to five species of wild plants growing on their residential plot, whereas the mean number of crop plants was 3.4. The total value of all plants was R1694 (US$ 269) per household per year, or approximately R4200 (US$ 667) per hectare of home garden per year. Wild plants represented 31% of the value of all plants grown on residential plots, relative to the 69% for domesticated crops (including fruit trees). Approximately 72% of the total value of all plant products was consumed by the household, and the remaining 28% was sold.
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  • Date Issued: 2000

The development of a geographic information systems based atlas of southern African freshwater fish, and its application to biogeographic analysis

  • Authors: Scott, Lucy Elizabeth Powell
  • Date: 2000
  • Subjects: Freshwater fishes -- Africa, Southern , Freshwater fishes -- Geographical distribution -- Atlases , Freshwater fishes -- Africa, Southern -- Geographical distribution -- Atlases , Geographic information systems
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5256 , http://hdl.handle.net/10962/d1005099 , Freshwater fishes -- Africa, Southern , Freshwater fishes -- Geographical distribution -- Atlases , Freshwater fishes -- Africa, Southern -- Geographical distribution -- Atlases , Geographic information systems
  • Description: A Geographic Information Systems (GIS) atlas of southern African freshwater fish was developed for the SADC countries from natural history collection specimens, hydrological, topographical and climatological data. The primary purpose of the development of the atlas of freshwater fish was the construction of a practical framework to transform vast amounts of existing biological data for use in research and management of aquatic resources. The database of freshwater fish collection specimens that was incorporated into the atlas, was developed in association with ALCOM (Aquatic Resources Management for Local Community Development Programme). The development of advanced computing and GIS technology has increased the scope of biological atlas projects by facilitating the integration of large amounts of spatial data to produce derived databases for specific applications. The atlas of freshwater fish was constructed using TNTmips GIS software as the most practical system available for managing and analysing biological data with a spatial component. The atlas contains 35 180 comprehensive distribution records of 735 species of fish. It has many applications as an inventory of ichthyofaunal spatial biodiversity, including those of conservation planning, environmental assessment and biogeographic research. Biogeographic studies have traditionally been subjective due to the logistical problems of working with large amounts of distribution data, although some small-scale quantitative research has been carried out in the past. The content of the atlas of freshwater fish is tested with respect to these previous studies, on known patterns of freshwater fish distributions, and the analytical capability of the atlas is tested and demonstrated with some new preliminary approaches to the analysis of freshwater fish distributions in southern Africa.
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  • Date Issued: 2000

The development of a geomorphological classification system for the longitudinal zonation of South African rivers

  • Authors: Rowntree, Kate M , Wadeson, Roy A , O'Keeffe, Jay H
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6722 , http://hdl.handle.net/10962/d1006799
  • Description: The recognition of the Reserve by the new South African Water Law poses new challenges for river scientists. The ecological water requirement or environmental flow is recognised by that part of the Reserve known as the ecological Reserve. If the ecological Reserve is to be implemented, it must first be defined and quantified for all river systems subject to water related developments. Standard procedures are being developed through the Resource Directed Measures (RDM) of the Department of Water Affairs and Forestry while monitoring the health of South Africa's rivers is taking place through the National River Health Programme (NRHP). Cost effective methods of developing spatial frameworks for both the RDM and NRHP are required. Concepts of longitudinal river zonation were developed by river ecologists in the 1960s and 1970s to assist in the classification of ecologically uniform stretches of rivers. This paper reviews the different zonation concepts and presents a geomorphological classification of South African river zones that is being applied to the RDM and NRHP. The classification is tested on three rivers, the Sabie, Buffalo and Olifants.
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  • Date Issued: 2000

The development of a pro forma document for use in police rape investigations in South Africa

  • Authors: Netto, Lauren Joy
  • Date: 2000
  • Subjects: Interviewing in law enforcement , Criminal investigation , Police questioning -- Forms , Rape -- Investigation -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3031 , http://hdl.handle.net/10962/d1002540 , Interviewing in law enforcement , Criminal investigation , Police questioning -- Forms , Rape -- Investigation -- South Africa
  • Description: This research developed a pro forma document for use in police rape investigations in South Africa. The immediate context for the research is the alarmingly high incidence of rape in South Africa. The rape statistics vary to an extent, largely due to the fact that a large proportion of the rapes that occur in South Africa are not reported to the police. These statistics expose the limited success of the South African Police Services (SAPS) in terms of investigating rape cases in this country, as well as the public perception of the effectiveness of the South African Police Services in this regard as evidenced by the non or under-reporting of rape in South Africa. The pro forma document is an investigative tool designed to standardise and systematise rape investigations by providing set guidelines for obtaining the essential information about each rape case. This is a prerequisite for Tender profiling, which involves predicting the relationship between offence and offender variables. Profiling can only be successful if the investigator obtains all the information about a crime. Hence the pro forma document, as an investigative instrument designed to access essential information about a crime, is a key requirement for the development of informed and accurate profiles of offenders. As a standardised form, the document will allow for systematic and thorough rape investigations in South Africa. The researcher employed the qualitative methodology of action research. This entailed involving the participants in all stages of the research process. The data was collected by means of focus group interviews with detectives from the Serious and Violent Crimes Unit and the Child Protection Unit in Grahamstown. Additional sources of data were various investigative documents that originated from a number of different countries. Analysis of the data followed a number of procedural steps specifically suggested for focus group interview research and involved a process of coding. The codes identified during the analysis provided the foundation for the items that were included in the pro forma document. In keeping with the action research approach, the participants were caned upon to evaluate the progress of the research after the initial data collection and analysis were completed, and a draft version of the pro forma document had been compiled. This feedback provided another source of data which contained suggestions for amendments to the pro forma document which the researcher implemented. The research process was hindered to a certain extent by the unpredictable nature of police work which influenced the data gathering procedure. This could point to a possible limitation of the research. Furthermore, the aim of the research was to develop a pro forma document for use in rape investigations in South Africa. This aim did not encompass marketing the document. Herein lies another possible limitation of the research in that the document has not yet been used and tested in real cases. A discussion of the research process includes issues involved in practically implementing the pro forma document in rape investigations.
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  • Date Issued: 2000

The development of a WAIS-III short form for use in South Africa

  • Authors: Rust, Annegret L
  • Date: 2000
  • Subjects: Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3047 , http://hdl.handle.net/10962/d1002556 , Wechsler Adult Intelligence Scale , Intelligence tests -- South Africa , Wechsler Adult Intelligence Scale -- South Africa
  • Description: The Wechsler Adult Intelligence Scale - 3rd Edition (WAIS-III) is the newest of the internationally recognised Wechsler family of intelligence tests. It has been improved in terms of its psychometric properties, neuropsychological assessment abilities and its content. This test is in the process of being standardised by the Human Sciences Research Council (HSRC) in South Africa. As the adapted South African version will be available shortly for use in the multicultural circumstances of South Africa, the application of the various aspects of this test needs to be investigated. This test is very comprehensive and thorough, however its one disadvantage is that it takes on average three hours to administer in its entirety. Thus there is a need to find ways in which to abbreviate the test for particular purposes when time is limited, for example in research, brief clinical assessments or neuropsychological screenings. The concept of abbreviating tests, including the earlier Wechsler intelligence test can be traced back to 1917, when it was asked if all the items on the Binet-Simon scale were required to give an accurate assessment of IQ (Levy, 1968). Since then there have been many short form suggestions made, with many different considerations in mind. These can be divided into two main approaches or methods. Firstly, the number of subtests of the scale can be reduced. Thus with the WAIS-III which consists of 14 subtests in total, an option is to use, for example only four of the subtests to get an estimate of a person's IQ. Secondly, the number of items in each subtest can be reduced. Thus only half the items or even only a third of the items on a subtest can be administered to get an estimate of the persons' performance on each subtest and in this way estimate their overall IQ. Both methods have been used on the WAIS and WAIS-R, although the reduction of the subtests is favoured. Both should now be validated and considered for use with the WATS-III in South Africa. Wechsler tests and their constituent subtests have been found to be differentially effected by race, education, language and socio-economic status (Kaufman, McLean & Reynolds, 1988; Nell 1999). These differences have also been found to impact on the short forms which are suggested, as certain subtests are considered to be more biased towards particular groups than others. Vocabulary and Block Design in particular bias testees who are not as westernised or acculturated towards a largely American and European culture (Kaufman, McLean & Reynolds, 1988). These differences, although often ascribed to race, language or socio-economic status can best be understood more broadly in terms of degree of acculturation (i.e. westernisation) (Shuttleworth-Jordan, 1996) and test-wiseness (Nell, 1999). In South Africa in particular, with its extreme cultural diversity these factors need to be carefully considered when developing short forms. In the present study the development of a short form appropriate to South Africa's diverse cultural circumstances will be approached, through a sample which has been stratified according to gender, first language (English vs. African), quality of schooling received (Private/Model C vs. DET) and level of education achieved (Matric vs. Graduate). Both a subtest reduction method and an item reduction method will be considered to arrive at a short form. The subtest reduction method will be considered further in an attempt to clarify which subtests would be more or less appropriate to include in a short form considering group differences. Finally the thesis will develop suggestions as to which short forms would be best for use in South Africa.
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  • Date Issued: 2000

The dynamics of an emerging outcomes-based educational approach in a second language English classroom

  • Authors: Westphal, Vivian
  • Date: 2000
  • Subjects: English language -- Study and teaching -- Foreign speakers -- South Africa Competency-based education -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1502 , http://hdl.handle.net/10962/d1003384
  • Description: Curriculum 2005 and outcomes-based education was introduced to South African educators in 1996 by the Minister of Education, Prof. S.M.E. Bengu as an alternative to the racially divided education system prior to the first democratic elections of 1995. The new curriculum was designed to transform the education system into a more equitable system by focussing on creating learners who would become creative thinkers, independent, productive workers and responsible, non-racial citizens. Learners would take a greater role in their own education and teachers would take on new roles as facilitators in the learning process. The new approach was introduced into grade 1 in 1998 and grade 2 in 1999. By using a modified ethnographic approach, this research project studies how one teacher has begun to think about Curriculum 2005 and implement an OBE approach to ESL teaching in a grade 2 classroom. It also focuses on gaining insights into how the teacher has attempted to make sense of the new curriculum in terms of her current practice and the training she has received in OBE. The ethnographic approach of the thesis has allowed the researcher to draw on many forms of data providing a holistic view. Tentative findings show that the teacher is experiencing difficulty in “unpacking” the underlying principles of OBE in terms of her current methods of teaching ESL. She continues to work from tacit knowledge. Because she has received very little training in OBE, she lacks the tools to become a more reflective practitioner. Despite this, her ESL lessons show a positive communicative approach to language teaching by focusing on stories, rhymes and songs as comprehensible input for the learners. The findings of this thesis tentatively suggest that unless teachers are given more adequate training and learning support materials, their classroom practices will remain relatively unchanged.
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  • Date Issued: 2000

The economic implications of trade policy reform in South Africa for the automotive industry in the Eastern Cape Province

  • Authors: Onyango, Donald Otieno
  • Date: 2000
  • Subjects: Automobile industry and trade -- South Africa -- Eastern Cape , South Africa -- Commercial policy
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:936 , http://hdl.handle.net/10962/d1002669 , Automobile industry and trade -- South Africa -- Eastern Cape , South Africa -- Commercial policy
  • Description: South Africa is no longer a pariah state and has been fully integrated into the global family of nations. With the country’s accession to multilateral agreements like the World Trade Organization (WTO), there has been pressure on the government to abandon its hitherto protectionist trade regime in favour of free and fair trade. Trade liberalisation has had profound implications for the country’s manufacturing sector in general, and the automotive industry in particular, which has seen tariff protection radically slashed and import restrictions greatly eased. Not only has the market share of domestic producers fallen, but increases in exports have to date not matched those of imports. As a result there has been a deterioration in the sector’s balance of trade and a reduction in employment levels, at a time when the country desperately needs to create new jobs. Recent developments, however, suggest that this scenario may be set to change. The thesis applies orthodox neoclassical and heterodox approaches to trade policy to an assessment of the likely economic impact of trade liberalisation on the automotive industry in the Eastern Cape, and by extension nationally. The thesis argues that reliance on orthodox trade theory to inform the direction of trade policy, especially in a developing country context, is unlikely to bring about an adequate increase in the level of exports and employment. This is because liberalisation of the import regime is likely to increase import levels without necessarily stimulating export levels, a scenario which serves to negate the presupposed benefits of liberalisation. The study uses information from surveys conducted on both motor vehicle assemblers and component manufacturing firms to investigate the effect of trade liberalisation on the sector in the Province and finds that, by and large, the motor assemblers have not fared as badly as expected and have in fact positioned themselves to export more vehicles and components. The components sector has had to contend with increased competition from cheaper imports. The thesis, while acknowledging that, as far as possible, free trade is an optimal position, nonetheless argues that governments still have an important role to play in the promotion of industrialisation. The scope of government intervention should, however, be limited to selective interventions which are aimed at counteracting market failure and facilitating innovation and the diffusion of technological know-how. The thesis argues that institution of supply side measures, such as the encouragement of research and development (R&D), skills development and industrial training, is necessary for sustained growth in the manufacturing sector to be realised. The thesis also finds that, contrary to expectations, the liberalisation of the automotive sector has not had the desired effects. Despite an increase in the value of automotive exports and an overall trend towards reduced net foreign exchange usage, employment levels are on the decline. The thesis also finds that without major export initiatives by both motor vehicle assemblers and component manufacturers, the future of the industry will be placed in jeopardy, especially with reduced protection and incentives.
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  • Date Issued: 2000

The effect of 6-Methoxy-2-Benzoxazolinone (6-MBOA) on indoleamine regulation and its possible role in depression

  • Authors: Tanda, Sindiswa Eunice
  • Date: 2000
  • Subjects: Tryptophan -- Physiological effect , Tryptophan -- Therapeutic use , Antidepressants
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3912 , http://hdl.handle.net/10962/d1003971 , Tryptophan -- Physiological effect , Tryptophan -- Therapeutic use , Antidepressants
  • Description: Tryptophan is an essential amino acid that is obtained from the diet. Approximately 98 % of ingested tryptophan is metabolized by the enzyme tryptophan 2,3-dioxygenase (TDO). The metabolism of tryptophan by TDO is an important determinant of tryptophan bioavailability to the brain for serotonin (5-HT) biosynthesis, an essential amine in affective disorders such as depression. Studies done on circadian rhythmicity of the enzyme activity have shown that, TDO activity is high during the scoto-phase (dark-phase), which is attributable to the de novo enzyme synthesis that occurs during this phase. 6-Methoxy-2-benzoxazolinontr-(6-MBOA), a structural analogue of melatonin (aMT) was shown to inhibit TDO activity in both the photo-phase (light-phase) and the scoto-phase with greater potency during the light-phase. Further studies were directed at demonstrating the effects of 6-MBOA on the brain tryptophan hydroxylase (TH) activity, which is a rate limiting enzyme in 5-HT biosynthesis and subsequently on 5-HT levels. The findings showed that, 6-MBOA induces TH activity with a concomitant rise in brain 5-HT levels. The blockade of 5-HT re-uptake into the presynaptic neuron leads to an increase in 5-HT available for the stimulatory action of 5-HT receptors. An attempt to establish whether the administration of 6-MBOA would block the binding of 5-HT to receptors on the synaptosomal membrane showed that 6-MBO A only inhibits the binding of 5 -HT at specific concentrations. In view of the positive effects imposed by 6-MBOA on brain 5-HT levels, urinary 5-hydroxyindole acetic acid (5-HIAA) excretion was measured before and after treatment with 6-MBOA. 5-HIAA excretion was found to be significantly increased after 6-MBOA treatment. Extensive research on the biosynthesis of pineal metabolites has been conducted in the past two decades. The pineal metabolites are synthesized from the precursor tryptophan. In order to obtain an overall picture of the effect of6-MBOA on pineal indole metabolism, an organ culture technique was employed. The results obtained showed that although 6-MBOA administration to rats caused a significant increase in aMT production, there was an insignificant increase in NAS production. This is an immediate precursor of aMT. Other pineal indoles were not affected at all by 6-MBOA administration. Furthermore, the production of pineal NAS and aMT showed an inter-individual variation with some animals producing very high, some very low and some produced average levels of these two metabolites in both photo and scoto-phase experiments. A study undertaken to investigate the circadian rhythm in endogenous aMT production using the competitive ELISA technique showed a clear pattern with high levels of aMT produced during the dark-phase and low levels ofaMT produced during the light-phase. Furthermore, the administration of6-MBOA to rats lead to a significant rise in endogenous aMT production.
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  • Date Issued: 2000

The effect of load carriage on selected metabolic and perceptual responses of military personnel

  • Authors: Ramabhai, Leena I
  • Date: 2000
  • Subjects: Marching -- Physiological aspects , Military art and science , Marching -- Psychological aspects , Lifting and carrying
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5111 , http://hdl.handle.net/10962/d1005189
  • Description: Taking a multi-disciplinary, integrated approach, the present study sought to examine selected physiological and psycho-physical parameters related to load carriage involving a 12 km march under military conditions. Military constraints hampered, but did not entirely inhibit the secondary aim of the study which concerned the effectiveness of relativising loads in order to normalise responses for all soldiers, irrespective of morphological diversity. Forty three subjects were measured in six groups using a test-retest experimental protocol. They were involved in a rest-broken 12 km march at 4 km.h⁻¹ under 40.5 kg absolute total load and under a relative load of 37% of body mass. Heart rates, ratings of perceived exertion (RPE) as well as area and intensity of discomfort were monitored for all subjects. Ten subjects were measured more extensively with regard to physiology using the Metamax, a portable ergospirometry system that provides all the data needed for a complete functional analysis of lung, heart, circulation and metabolic activity. Physiological responses (fc; fb; V̇T; V̇E; V̇O₂; EE; V̇CO₂; R; T°) indicated subjects were not severely physically taxed and that the loads imposed constituted a sub-maximal demand. Moreover, there appeared to be a limited cumulative effect over the 3.5 h. Data from the first and third hours were similar, while the significantly higher responses in the second hour reflected the challenge of the undulating terrain encountered during this section of the march. All responses during the Relative load conditions mirrored those of the Absolute load condition but, because the demands were less, the trends occurred at a reduced level. Furthermore, the reduction in inter-individual variability indicates that relativised load carriage tends to stress the soldiers in a more uniform manner. All "local" RPE responses were higher than "central" ratings, suggesting soldiers were in good cardiovascular condition and experienced marginally more strain in the lower limbs. There was increased perceived strain corresponding to the increase in gradient, with little cumulative effect over the three hours. The shoulders and feet were the two regions in which most discomfort was experienced; the shoulders being the worst area in the first hour and the feet being rated the worst after the third hour of marching. This study clearly demonstrates the probability of a significant improvement in mean combat-readiness following loaded marching by showing that, if loads are set at levels commensurate with individual capabilities to carry them without undue strain, unnecessary physical demands experienced by smaller, more gracile soldiers are reduced.
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  • Date Issued: 2000

The evolution of the Brosterlea Volcanic Complex, Eastern Cape, South Africa

  • Authors: Surtees, Grant Bradley
  • Date: 2000
  • Subjects: Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4944 , http://hdl.handle.net/10962/d1005556 , Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
  • Description: Detailed field mapping (Map, Appendix B) has been conducted in and around the boundaries of a 14x18km, volcanic complex 35km northeast of Molteno in the Eastern Cape Province, South Africa. The structure is interpreted as a subsidence structure, and is filled with two volcaniclastic breccias, numerous lava flows, a number of sedimentary facies, and lies on a base of Clarens Formation overlying Elliot Formation rocks. This is an important study because 'widespread, voluminous fields of basaltic breccias are very rare (see Hanson and Elliot, 1996) and this is the first time that this type of volcanic complex and its deposits have been described. Detailed analyses of the two volcaniclastic breccias revealed changes in colour, clast types, clast sizes, and degree of alteration over relatively short distances both vertically and laterally within a single breccia unit. The variation in clast sizes implies a lack of sorting of the breccias. The lower of the two volcaniclastic breccias fills the subsidence structure, and outcrops between the Stormberg sedimentary sequence and the overlying Drakensberg basalts and was produced from phreatomagmatic eruptions signalling the start of the break-up of Gondwanaland in the mid-Jurassic. The upper volcaniclastic breccia is interbedded with the flood basalts and is separated from the lower breccia by up to 100m of lava flows in places, it is finer-grained than the lower volcaniclastic breccia, and it extends over 10km south, and over 100km north from the volcanic complex. The upper breccia is inferred to have been transported from outside the study area, from a source presumably similar to the subsidence structure in the volcanic complex. The pyroclastic material forming the upper breccia was transported to the subsidence structure as a laharic debris flow, based on its poorly sorted, unwelded and matrix-supported appearance. However, both breccias are unlikely to have been derived from epiclastic reworking of lava flows as they contain glass shards which are atypical of those derived from the autoclastic component of lava flows. The breccias are therefore not "secondary" lahars. There is also no evidence of any palaeotopographic highs from which the breccias could have been derived as gravity-driven flows. Based on the occurrence of three, 1m thick lacustrine deposits, localised peperite, fluvial reworking of sandstone and breccia in an outcrop to the south of the subsidence structure, and channel-lags encountered only in the upper units of the Clarens Formation and only within the subsidence structure, the palaeoenvironment inferred for the subsidence structure is one of wet sediment, possibly a shallow lake, in a topographic depression fed by small streams. Magmatic intrusions below the subsidence structure heated the water-laden, partly consolidated Clarens Formation sandstones, causing the circulation of pore fluid which resulted in the precipitation of minerals forming pisoliths in the sandstones. Intruding magma mixed, nonexplosively, with the wet, unconsolidated sediments near the base of the Clarens Formation (at approximately 100m below the surface), forming fluidal peperite by a process of sediment fluidisation where magma replaces wet sediment and cools slowly enough to prevent the magma fracturing brittly. Formation of fluidal peperite may have been a precursor to the development of FCIs (Fuel Coolant Interactions) (Busby-Spera and White, 1987). The breccias may represent the products of FCIs and may be the erupted equivalents of the peperites, suggesting a possible genetic link between the two. The peperites may have given way to FCI eruptions due to a number of factors including the drying out of the sediments and/or an increase in the volume of intruded magma below the subsidence structure which may have resulted in a more explosive interaction between sediment and magma. Phreatic activity fragmented and erupted the Clarens Formation sandstone, and stream flows reworked the angular sandstone fragments, pisoliths and sand grains into channelised deposits. With an increase in magmatic activity below the subsidence structure, phreatic activity became phreatomagmatic. The wet, partly consolidated Clarens Formation, and underlying, fully consolidated Elliot Formation sediments were erupted and fragmented. Clasts and individual grains of these sediments were redeposited with juvenile and non-juvenile basaltic material probably by a combination of back fall, where clasts erupted into the air fell directly back into the structure, and backflow where material was erupted out of the structure, but immediately flowed back in as lahars. This material formed the lower volcaniclastic breccia. A fault plane is identified along the southwestern margin of the subsidence structure, and is believed to continue up the western margin to the northwestern corner. A large dolerite body has intruded along the inferred fault plane on the western margin of the structure, and may be related to the formation of the lower volcaniclastic breccia, either directly through fluidisation of wet sediment during its intrusion, or as a dyke extending upwards from a network of sill-like intrusions below the subsidence structure. Geochemical analysis of the Drakensberg basalt lava flows by Mitchell (1980) and Masokwane (1997) revealed four distinct basalt types; the Moshesh's Ford, the Tafelkop, the Roodehoek, and the Vaalkop basalts. Basalt clasts sampled from the lower volcaniclastic breccia were shown to belong to the Moshesh's Ford basalt type which does not outcrop in situ within the subsidence structure. This implies that the Moshesh's Ford basalts were emplaced prior to the formation of the lower volcaniclastic breccia, and may have acted as a "cap-rock" over the system, allowing pressure from the vaporised fluids, heated by intruding basalt, to build up. The Moshesh's Ford basalt type was erupted prior to the resultant phreatomagmatic events forming the lower volcaniclastic breccia.
  • Full Text:
  • Date Issued: 2000

The experience of multi-cultural communication within a South African organization

  • Authors: Lesch, Anthea M
  • Date: 2000
  • Subjects: Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:3008 , http://hdl.handle.net/10962/d1002517 , Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
  • Description: This research study was conducted in an attempt to explore the experience of multicultural communication within a South African organization. To this end employees, representing both Black and White culture, within a South African organization in the throes of transformation, were accessed. A model of managing diversity, focussing on the personal, interpersonal and organizational levels, was utilized in an attempt to uncover the nature of the experience of multi-cultural communication within Company X. A qualitative research design, and more specifically the case study method was employed in this study. Consistent with the case study approach a number of data sources were accessed. The primary data source consisted of a 3-stage interview process. Other data sources included documentary sources and company publications. By accessing multiple data sources, the researcher attempted to gain a holistic understanding of the experience of multi-cultural communication. It was found that the societal context of our post-Apartheid society exercises a profound influence on multi-cultural communication. Under Apartheid cultural separation was promoted. Diverse peoples thus have little common basis for interaction and view each other with skepticism and distrust. This exercises an effect on the personal and organizational levels of the managing diversity model. Influences at the personal level relate to the cultural paradigms of the individuals which provide the rules governing interactions and affect judgements of acceptable and unacceptable behaviours. Issues at the organizational level relate to its structures and policies which are still based on the “white is right ideology”. These issues, in turn, affect the interpersonal level of managing diversity, i.e., where the interactions occur, causing “communication short circuits” within the process of multi-cultural communication. In order to deal with failed multi-cultural communication, the individuals have developed a number of coping strategies. The results of the study indicate that both the organization and its employees share a responsibility for creating an environment that will facilitate effective multi-cultural communication.
  • Full Text:
  • Date Issued: 2000

The exploitation of Upogebia africana (Crustacea: Thalassinidae) for bait in the Knysna Estuary

  • Authors: Hodgson, Alan N , Allanson, Brian R , Cretchley, Robyn
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6924 , http://hdl.handle.net/10962/d1011911
  • Description: The activities of people collecting Upogebia africana for bait at six popular collecting sites in the Knysna Estuary were monitored from February 1995 until April 1996. Three groups of bait harvesters were identified on the basis of their source of income: subsistence fishers who rely on bait collecting and fishing for their income; supplementary fishers who catch fish to supplement their income; leisure anglers who draw no income from fishing. Two groups of collectors were identified based on methods of collecting bait and fishing: leisure anglers who collect bait using a prawn pusher or pump and fish using a rod and tackle; non-leisure fishers who collect using tin cans and fish with hand or planted lines. The average harvest of bait per collecting trip by leisure anglers was 59 mud prawns, whereas non-leisure fishers took 101 animals, twice the legal limit. The numbers of bait collectors present per mud bank were found to be highest on public holidays ([horizontal bar over]X = 43.5) and higher during the summer holidays ([horizontal bar over]X = 16.5) than during the spring/summer ([horizontal bar over]X = 8.6) and autumn/winter ([horizontal bar over]X = 4.6) periods. Most collectors spent 11-30 minutes on the mud banks. It was estimated that 1.86 x 10[superscript 6] U. africana or about 740 kg (dry mass) was removed by bait collectors annually from the six bait-collecting sites studied. This represented about 8.5% of the mud prawn stocks at these sites and about 0.9% of the entire estuary stock. 85% of the mud prawns taken as bait was removed by 77% of the bait collectors who were the non-leisure fishers.
  • Full Text:
  • Date Issued: 2000

The geomorphological impacts of impoundments, with particular reference to tributary bar development on the Keiskamma River, Eastern Cape

  • Authors: McGregor, Gillian Kathleen
  • Date: 2000
  • Subjects: Rivers--South Africa--Regulation , Rivers--South Africa--Regulation--Environmental aspects , Rivers--South Africa--Eastern Cape , Geomorphology--South Africa--Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4835 , http://hdl.handle.net/10962/d1005510 , Rivers--South Africa--Regulation , Rivers--South Africa--Regulation--Environmental aspects , Rivers--South Africa--Eastern Cape , Geomorphology--South Africa--Eastern Cape
  • Description: The primary aim of this research was to develop and test a conceptual model of the geomorphological impacts of river regulation, based on a review of relevant international literature. It was motivated by the fact that there is very little local information on the topic, and it was intended that the model might provide a starting point for assessing the impact of impoundments on South African river systems. At present most research in South Africa on the impact of impoundments is undertaken from an ecological perspective. In order to manage our water resources sustainably it is necessary to have a better understanding of our river systems. South Africa is characterised by a variable climatic regime and, in order to supply water to the various user sectors of the nation, dams have to be larger than elsewhere in the world, to trap most of the mean annual runoff and provide a reliable water store (Alexander, 1985). South African dams have been designed to reduce the variability of a naturally variable regime. The impact of flow regulation in dryland rivers has been described as 'ecologically catastrophic at every level.' It is therefore hardly surprising that the impact of these dams on the natural functioning of rivers is substantial. The conceptual model showed that there are many responses to river impoundment, which are varied and complex, both in time and space. Responses or secondary impacts depended on the nature and degree of the primary impact or process alteration, on the sediment and flow regime of the river. High flows were affected in all cases and low flows were affected in most cases. The simplest form of change was Petts' (1979) concept of 'accommodation' of the regulated flow within the existing channel form. More complex responses occUrred where the channel perimeter was unstable, or where tributaries introduced fresh sediment loads. The river could adjust its long profile, cross sectional area and substrate composition by aggradation or degradation. The conceptual model was used in the Building Block Methodology to predict impoundment impacts at Instream Flow Requirement workshops on the Berg, Komati and Bivane rivers. It was also used in assessing the impact of the Sandile Dam on the Keiskamma river. Tributary junctions were identified as likely sites of change, and the morphology of bars at these junctions was investigated. Due to the number of variables affecting the sediment and flow regime in the system, and due to the fact that the primary impacts were not substantial, it was not possible to come to any decisive conclusions. It would seem that the dam is well located in the catchment, and, because the water is not heavily utilised, the secondary impacts are not great. The conceptual model was found to be a useful basic tool which might contribute to a better understanding of our river systems, and ultimately to improved sustainable resource management.
  • Full Text:
  • Date Issued: 2000
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